character controller was not working when the apply rootmotion option is enabled?

hai to all...i try to move a humanoid character.....i have two doubts.... 1). If i move my character using transform.translate function it doesnt goes in the straight line..i want my character to move in a straight path.......

2). my second doubt is....i added the character controller to the human sample....if i enable the apply root motion option the collision will occurs.....otherwise if i remove the apply rootmotion option collisions are not happened...other than my player all other objects having box collider....i dont want use the rigid body....i want to control the collisions using only character controller.....if i enable the apply rootmotion everything is ok....it will react what i want...but i want this to happen without the apply root motion option enabled.....i want to control my object only via the script....

Thanks in advance......